Filtration is a process of removing contaminants from a stream of either gas or liquid. Most liquid filtration methods use a pump located beneath a tank to feed a liquid, such as water, through tubular filters or bag filters before passing into a liquid reservoir. With continued use, the filter will slowly accumulate unwanted solids, resulting in a decrease in the flow rate due to the increased pressure drop caused by the accumulated solids on the surface of the filter.
When the filter surface is significantly clogged, causing a significant reduction in fluid-flow, the filter should be either cleaned or replaced. Such a maintenance procedure, however, can be costly. During the procedure, the filtration system must be stopped, resulting in lost production. Additionally, the maintenance costs for labor and replacement filters are typically expensive.
Most traditional self-cleaning filters use a backwash method, which reverses the direction of water flow during the cleaning phase. The backward flow dislodges deposits on the filter surface and removes the contaminants from the filter system. One of the drawbacks of this backwash method is the consequential waste of clean water used to clean the filters. Additionally, suitable piping arrangements can become unnecessarily complicated in order to accommodate the backwash flow. A backwash concept may not be practical for numerous filtration systems such as plants which utilize high flow rates in light of the need for large pipe diameters and large quantities of clean water for the backwash to be effective.